The present invention relates to a 1,2,4-oxadiazole derivative which can inhibit monoamine oxidase B (hereinafter referred to as "MAO-B") and a method for preparing the derivative.
It has been believed that about a hundred of thousand persons presently suffer from Parkinson's disease in the country and the onset thereof is in general observed in aged persons of 50-year-old or higher. The population of the aged would be more and more increased in the future and thus there has been a strong need for the development of medicines effective for treating Parkinson's disease.
It has been considered that Parkinson's disease is caused due to the reduction in the ability of producing dopamine which is essential and indispensable as a neurotransmitter in the brain when one suffers from nigrostriatal disorder in the basal nucleus region of the brain. Presently, there has commonly been administered L-dopa as a precursor of dopamine for treating Parkinson's disease. The administration of an MAO-B inhibitor permits a significant extension of the residence time of dopamine formed through the metabolism of the L-dopa in the brain and thus can enhance the efficacy thereof. Moreover, it would further allow the reduction of dose of the L-dopa and, therefore, it likewise serves to substantially relieve side-effects of the L-dopa such as nausea, arhythmia, orthostatic hypotension and symptoms of depression.
There have been investigated the MAO-B inhibitors on the basis of these basic assumptions and d,l-Deprenil has first been developed as a medicine for the treatment of Parkinson's disease among other compounds. The effectiveness of this compound has clinically been proved in the United States and Europe and it has been practically used as a medicine for treating this disease.